MEDRADSC 3S03 Lecture Notes - Lecture 6: Sarcoma, Absorbed Dose, Collimator

• School: McMaster University
• Department: Medical Radiation Sciences
• Course: MEDRADSC 3S03
• Professor: Dawn Danko

Document Summary

What happens if the setup conditions are not the same as the calibration conditions. Any change in setup conditions relative to calibration conditions will impact the absolute dose rate @ dref. Correction factors to account for the differences between calibration conditions and actual setup conditions can be applied to arrive at the time required to deliver the prescribed dose. Dose rate at a point (dref) is a result of contribution of dose from primary photon beam + scattered photons. Scatters affect the dose rate in the patient. How does the scatter affect the dose in the patient. Two fields with the same area do not necessarily contribute the same scatter contribution to the point of measurement (dref) Equivalent squares (eq2) table provides the square field size that provides the same scatter contribution at dref as the rectangular field being used. The eq2 is used to look up correction factors (tpr or %dd, sc, sp)